Audio Science Review (ASR) Forum

Reviews, Technical Articles, Hardware Teardowns and Measurements of Audio Products

Time for another bargain DAC, the Topping D30 DSD/PCM DAC. It retails for a mere $120 on Amazon including shipping: https://www.amazon.com/TOPPING-Decoder-Coaxial-Optical-CS4398/dp/B01L1SDKUQ


I will do a hardware tear down later but for now, the enclosure seems nice quality and a step above typical DIY shops. The unit is externally powered and surprisingly with a Topping branded switchmode power supply. Typically people buy these in open market instead of having one made for them with custom label. It has higher than normal output of 15 volt which helps it with higher output drive as you see later.

Capabilities are excellent with PCM up to 192 Khz and DSD up to DSD128. Furthermore, the unit comes with not only USB input but also coax and optical S/PDIF inputs. Nice!

Measurements
As always I started with J-Test to measure noise floor and jitter. For reference, I also test the Behringer UMC204HD, our king of low...
Hello everyone. Here is another episode in my look inside different high resolution samples. Here, I analyze the free samples from the great indie label, Sound Liaison which as 2L, are kind enough to provide these clips for us to use: https://www.soundliaison.com/all-categories/6-compare-formats

In this look, I examine the DXD files at 352 Khz using another program, MusicScope:

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This allowed me to play the files even in DXD and dsd formats.
I have been reviewing a lot of low cost DACs recently. I wanted to have a high-performance DAC as a reference. My best DAC is in my audio system and pain in the neck to relocate back and forth. So I set out to find a DAC in $2000 range (my cost). Idea was to have a very low noise/low distortion DAC that would be revealing of any tweaks put in front of them.

After getting suggestions from the forum, I short-listed it to Benchmark and Exasound. Both of them provide measurements on their site which gave me confidence of good design. As it turns out, I reached out to Exasound and they immediately answered so I went with them. I asked for accommodation pricing on E32 DAC and I received a good discount. As a professional courtesy I don't want to say how much that is. Suffice it to say it is similar to dealer margin for high-end products. Should this have been a transaction with someone I know, the discount is usually 10 to 20% higher. Still, I thought it was a reasonable offer and I received the unit from Canada a couple of weeks ago.

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The retail price of E32 is $3,500 so not cheap at all.
The third-day was a rather short one for me since the show closes early. But also because I attended an amazing presentation by Avalon as you will see later. It capped a very nice show and a relaxing one. I hope the show was successful for the organizers and it continues.

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Here is my coverage of Day 2 of 2017 Rocky Mountain Audio Fest. As this was a full day, there was a lot more to cover. Hope you find it enjoyable and possibly informative.

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Hello you all. So the day 1 at the Rocky Mountain Audio Fest (RMAF) came to a close. It was a calm and "orderly" day with little to gripe about :). Being part of the press, I did not have to wait in this line where last year they could not find my badge. :)

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The line had died a few hours later.

The rooms had light to medium attendees. But when I asked a few companies what traffic they were seeing, they all said it was quite high and they were very satisfied with it seeing how it is not the weekend.

The weather outside is perfect with leaves starting to turn and super comfortable temps. But what the heck is going on here???
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Monday is the day I fly out! How do we go from 70s to 30s with snow and then back to near 70s???? It does not compute!

Had great number of conversations with industry folks. Unfortunately i can't share much of it with you all. :D

Overall, nice, relaxing and...
The Henry Engineering Matchbox II was loaned to me by a member for measurements and hardware teardown/review. I am not sure how well known this DAC is. It is targeted toward television broadcast world. It unusually has both ADC and DAC plus professional AES/EBU output (balanced version of S/PDIF). In that regard, it appropriately only has balanced inputs and outputs.


Retail price is fairly high for consumer market but appropriate for professional use at $479.

Specs are rather modest, stopping at just 48 Khz sampling and bit depth of 16 bits. Again, this is fine for video applications where 48 Khz sampling is standard and 16 bits sufficient.

Measurements
As always, my go-to measurement is 24-bit, 48 Khz J-test signal. I had not noticed that this device is limited to 16 bits when I did the testing so the 24-bit depth of the signal is lost on it. Indeed, that shows up in the measurements:

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The...
I was recently asked about merits of S/PDIF versus USB for audio DACs. It has been said that S/PDIF was designed for audio whereas USB is a computer interface. And that makes USB noisier and less desirable interface.

I think most of you know my opinion on this. But just in case, I believe USB to be a superior and more "correct" interface for audio. Problem with S/PDIF is that it makes the source the "master," forcing the DAC to chase its timing. This means that if the source S/PDIF signal is not very clean, it can impact target DAC performance. Fortunately over the years S/PDIF interface has been perfected a lot and even in low cost implementation it can be excellent.

Still, there is no reason to have this antiquated architecture. Using asynchronous mode USB, the DAC can set the cadence using a high-performance clock and force the source, in this case a computer or streamer, to follow it.

Yes, there is some risk of noise here as USB is a much more complicated interface...
This is a review of the Musical Fidelity V-DAC II including measurements. Member Ron Party was kind enough to l0an this to me. This is an older DAC, dating back to 2012 or so and retailed for $379. It comes with an external power supply which looks to be a linear one.

As usual, my first measurement is J-Test signal at 48 Khz sampling and 24 bits. Here is the outcome as compared to iFi iDSD which is a much newer DAC at similar price point:

As we see there, the noise floor of Musical Fidelity V-DAC II is lower than iFi iDSD even though its output is higher (i.e. has a better signal to noise ratio). Just eyeballing it, it seems to have 5 to 6 db advantage over iFi.

Given the linear power supply, its output is free of mains related harmonics. So overall, a very nice showing here.

I have also shown the performance of V-DAC using both its USB input and S/PDIF. S/PDIF was generated from my USB port using an Audiophilleo USB to S/PDIF converters. As...
The previous thread on DAC fundamentals provided an overview of conventional (Nyquist) DACs. This thread will introduce oversampling and the delta-sigma architecture that dominates the DACs used in consumer audio gear today.

A few definitions:

Nyquist = fs/2 = 1/2 the sampling frequency. This is the highest frequency that a sampled system can correctly capture and reproduce. Any higher, and the frequency information is lost. Note that Nyquist applies to the highest frequency in the signal, so an audio system can reproduce a 20 kHz sine wave ( a single tone) but not a 20 kHz square wave (which has many higher harmonics). A system sampling at frequency fs, e.g. 40,000 cycles per second (40 kHz), can acquire up to (but not including) 20 kHz signals.

Oversampling refers to how much "extra" bandwidth, or sampling rate, we have relative to the Nyquist rate. For the...